A permanent magnet synchronous motor has advantages such as high power density and good speed regulating performance, and is widely applied in various electric devices.
Currently, electric devices become necessities of daily life, and power consumption of a great quantity of electric devices grow with each passing day. Motors take up the majority of power energy consumed by electric devices. To reduce power consumption of the motor, currently, an FOC (Field Oriented Control—field oriented control) technology is used to control power supply to the motor.
When the FOC technology is used to control power supply to the motor, a position of a rotor needs to be learned in real time. In the prior art, a position sensor is usually used to detect the position of the rotor. Among numerous position sensors, a Hall sensor is widely applied because the Hall sensor has advantages such as high reliability, low costs, and easy to install.
However, restricted by manufacturing and installation techniques, a Hall sensor inevitably has an installation error during installation. Consequently, there is an error between a rotor position detected by the Hall sensor and an actual rotor position. This error affects precision of controlling the motor by using the FOC technology, causing abnormal phenomena such as a decrease in efficiency of the motor, a start failure, or even a reverse start.
To address an installation error of the Hall sensor, currently, a main compensation means is to manually detect and determine an installation error of the Hall sensor according to a phase relationship between an output signal of the Hall sensor and a back electromotive force of a permanent magnet synchronous motor, and perform compensation on the error. Such a compensation means has low efficiency and high labor costs.